Helicopter with one or more rotors having controllable ailerons



June 15, 1948. LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE RQTORS HAVING CONTROLLABLEAILERONS Fi1d Dec. 8, 1942 18 Sheets-Sheet 1 ,lNVENTdR Fred lama 9m? TTdRNEY ucdi UH 0i 3511815, 1948. LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed Dec. 8, 1942 18 Sheets-Sheet 5 INVENTOR BY 2521i OldZ/Of ATTORNEY search R00 Jun 15, 1948.

F. LANDGRAF HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS 18 Sheets-Sheet 4 Filed Dec. 8, 1942 IN V E NTOR F e0 dandy/0f i w/ ATTORNEY an 2 1 I U J u 5 7 Z 2 4 r E U Q w I 5 m 2 m w. W 8 26 95 2 3% 2% E \n-\ 9 m x UDU! UH HUU June 15, 1948. F. LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE ROTQRS HAVING CONTROLLABLE AILERONS Filed D90. 8, 1942 18 Sheets-Sheet 5 v INVENTOR Fred 1 army/0f BY ATTO R N EY 8 Sheets-Sheet 6 l N V E NTOR Ff Lana grai 2mm ATTOR N EY F. LANDGRAF HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed Dec. 8, 1942 J1me 15, 1948.

F. LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE ROTORS HAVING I CONTROLLABLE AILERONS Filed Dec. 8, 1942 18 Sheets-Sheet 7 I NV ENTOR Fred dandy/0f BY ATTORNEY aearcn WOC Q66! UH H0017 June 15, F N G 2,443,393

w; HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed Dec. 8, 1942 18 Sheets-Sheet 8 gI i l N V E NTOR ATTORN EY 9mm RUUI F. LANDGRAF June 15, 1948.

HELICOPTER WITH ONE OR MORE ROTORS HAVING CUNIROLLABLE AILERONS l8 Sheets-Sheet 9 Filed Dec. 8, 1942 l NVENTOR F 80 larmymf B yf M ATTORNEY kw/m Room 18 Sheets-Sheet 1 lNVENTOR Fred la a raf BY ATTORNEY F. LANDGRAF lune 15, 1948.

HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed Dec. 8, 1942 A UH mum Jim 15, 1943. F, LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed D60. 8, 1942 18 Sheets-Sheet 11 22/ 2/0 Q23 I 26 m 5 38 2/6 5/0 IN v E NTOR Fred [and rm ATTORN EY F. LANDGRAF Ju ne 15, 1948.

HELICOPTER WITH ONE OR MORE ROTQRS HAVING CONTROLLABLE AILERONS 18 Sheets-Sheet 12 Filed Dec. 8, 1942 I i iii 36 \NVENTOR Fred 0 agraf BY ATTORNEY imam-i1 mom -ANDGRA HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS l8 Sheets-s 13 Filed Dec 8 942 wiune 15, 1948.

HELICOPTER WITH ONE OR MORE ROTORS HAVING l8 Sheets-Sheet 14 Filed Dec. 8, 1942 \N V ENTOR fi'ea 000 raf ATTORNEY lun 15, 1948.

F. LANDGRAF HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS 18 Sheets-Sheet 15 Filed Dec. 8, 1942 INVENTOR Fed Lona rm ATTORNEY June 15, 1948. LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed Dec. 8, 1942 18 Sheets-Sheet l6 INVENTOR 5290 L0 ograf ATTO R N EY F. LANDGRAF ziune 15, 1948.

HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS l8 Sheets-Sheet 17 Filed Dec. 8, 1942 l N V E NTOR Fred [and raf 6 440 ATTORNEY UG! L4H MUL Jane-15, 1948. LANDGRAF 2,443,393

HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERONS Filed Dec. 8, 1942 18 Sheets-Sheet l8 INVENTOR Fred Kandy/02" BY ATTO R N EY Patented June 15, 1948 HELICOPTER WITH ONE OR MORE ROTORS HAVING CONTROLLABLE AILERON S Fred Landgraf, Los Angeles, Calif.

Application December 8, 1942, Serial No. 468,196

7 Claims. 1

This invention relates to airplanes, and particularly to helicopters.

Such airplanes are characterized by the provision of one or more air screws or rotors having axes of rotation substantially vertical. Suitable rotation of the air screws thus produces air reactions on the airscrew blades such that the resultant of the air forces is substantially vertical and opposite to the force of gravity. Properly controlled and directed, this force may be used to raise or lower the helicopter at a steep angle, or to cause it to move sideways, backward or forward either slowly or at high speed.

It is one of the objects of this invention to improve in general, airplanes of this character, In this connection, control of the helicopter is attained by control of the pitch of the air screw, or by control of ailerons carried by the blades of the rotor or screw.

As heretofore mentioned, the wings or blades of the helicopter rotor are each provided with an aileron on its trailing edge. These ailerons are so arranged that they may be maintained in a fixed position with respect to the blade. However, by the aid of a control mechanism, it is optionally possible to cause the ailerons to move through a cycle, so that for each revolution of a rotor, the ailerons of all the blades attain a maximum departure from neutral at any desired position of the blade in its rotating cycle. The amplitude of the aileron motion as well as the cyclic position of the blade where aileron displacement is maximum are both under the control of the pilot. By appropriate joint control of te ailerons of both rotors, the air forces on the blades may be modified so as to produce rolling or pitching moments or combinations thereof in addition to the vertical lifting force previously mentioned. The resultant eflects upon the direction of flight of the helicopter are well-known to a pilot; it is suflicient herein to point out the features of the aileron controls.

It is another object of this invention to provide a simple and thoroughly reliable control for operating the ailerons; and in this connection it is still another object of the invention to make it possible to test the aileron controls when the helicopter is grounded.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of the invention. For this purpose there is shown a form in the drawings accompanying and forming part of the present specification. This form will now be described in detail, illustrating the general principles of the invention: but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is an elevation of a helicopter incorporating the invention, part of the fuselage being broken away, and the disposition of the control operating parts, and of the power drive,

of the helicopter being illustrated in diagrammatic form within the main outline of the fuselage;

Fig. 2 is a top plan view of the helicopter illustrated in Fig. 1;

Fig. 3 is an enlarged sectional view taken along the plane 3-3 of Fig. 2;

Fig. 4 is a sectional view taken along plane 4-4 of Fig. 3;

Figs. 5 and 6 are detail sectional views on an enlarged scale, taken along the correspondingly numbered planes of Fig. 3;

Fig, '7 is an enlarged fragmentary elevation, partly broken away, looking in the direction of the arrow 1 of Fig. 3;

Fig. 8 is a fragmentary view of one of the rotors, only one of the rotor blades being shown completely, the other two rotor blades being broken away, the rotor shown in this figure being the one disposed on the left hand side of the helicopter;

Figs. 9 and 10 are horizontal views, mainly in section, of one of the rotor blades taken through the axis of the spar upon which the blade is supported; the blade chosen in this instance being the blade shown in Fig. 8;

Figs. 11, 12, 13 and 14 are sectional views taken glong correspondingly numbered planes of Fig.

Fig. 15 is a sectional view taken along plane l5|5 of Fig. 10;

Fig. 16 is an enlarged fragmentary vertical sectional view taken along plane l6--l6 of Fig. 9, but with the supporting spar removed, and parts being broken away to reduce the over-all length of the figure;

Fig. 17 is a horizontal section taken along plane ll-l'l of Fig. 16, with the supporting spar removed;

Figs. 18 and 19 are plan views of the spring hinge members adapted to cooperate to support a blade adjustably with respect to its supporting spar;

Fig. 20 is a fragmentary cross section, on an enlarged scale, through a rotor blade showing the action of the hinge members illustrated in Figs. 18 and l9;

Figr zl is a fragmentary plan view, partly in section, of the outer end portion of a rotor blade such as illustrated in Fig, 8, part of the figure bein broken away and illustrating the mechanism for controlling the aileron;

Figs. 22, 23, 24 and 25 are fragmentary sectional views on an enlarged scale, taken along the correspondingly numbered planes of Fig. 21;

Fig. 26 is a detail sectional view taken along the plane 2626 of Fig. 22;

Fig. 27 is a vertical section taken along the plane 21-21 of Fig. 2, a portion of the body of the helicopter being removed;

Figs, 28 and 29 are sectional views taken on correspondingly numbered planes of Fig. 27;

Fig. 30 is a plan view, partly in section, of a portion of the power transmission mechanism for driving the rotors;

Fig. 31 is a sectional view taken along the plane 3 l-3l of Fig. 30;

Fig. 32 is a sectional view, taken along the plane 32-32 of Fig. 31;

Fig, 33 is a pictorial diagram showing one part of the aileron control;

Fig. 34 is a sectional view taken along plane 3434 of Fig. 33;

Fig. 35 is a diagram similar to Fig. 33, of another part of the aileron control;

Fig. 36 is a pictorial diagram showing the mechanism for controlling the pitch of the rotors;

Figs. 37, 38 and 39 are detail sections taken along correspondingly numbered planes of Fig. 36;

Figs. 40 and 41 are diagrams illustrating the manner in which the rotor controls may be caused to effect the flight of the helicopter;

Fig. 42 is a diagram explaining the action of the aileron control; and

Fig. 43 is an enlarged detail section of the universal joint utilized in connection with the aileron control.

The general outlines of the helicopter are illustrated most clearly in Figs. 1 and 2. The fuselage may be made of any appropriate material; a plywood skin is indicated in the present instance. The fuselage terminates in a vertical tail 2 at the rear. In the grounded position of Fig. 1, the helicopter is shown generally as supported by the aid of landing gear incorporating wheels 3 and 4. Any appropriate landing gear, retractible or otherwise, may be used.

Accommodations for the pilot may include a seat in the forward portion of the fuselage. The front of the fuselage I is equipped with windows, such as 6 and 1.

A pair of rotors 8 and 9 are arranged to provide the propelling forces for the helicopter, These rotors are arranged for rotation on substantially parallel axes Ill and II. They are appropriately supported upon the outrigger structures I2 and 13, shown as joined to the fuselage I. These outriggers, as Well as all other parts of the helicopter body, may be made as heretofore mentioned of appropriate light material such as a light metal alloy, or plywood.

If wheel type or float type alighting gear is provided, the arrangement may be such that in the grounded position the rotor discs incline downward at the front, thus providing a forward component of the rotor thrust force which may be utilized to propel the craft on land or water.

The relationship of the rotor axes with respect to the fuselage is such that when the helicopter is in flight at normal cruising speed, the fuselage may be substantially level, and the rotor discs may be inclined downward at the front, so that a part of the rotor thrust may be utilized for propulsion. The automatic provision for maintaining this flight attitude has been heretofore explained in connection with the location of the center of gravity.

As shown most clearly in Fig. 2. the distance between the rotor axes I0 and H is considerably less than the outside diameter of the rotors. If the left hand rotor 8 rotates in a counterclockwise direction as indicated by the arrow a and if the right hand rotor 9 rotates in a clockwise direction as indicated by the arrow b, by appropriate synchronization of the rotor operation, the blades of the rotors will pass each other without interference. The manner in which the synchronous drive is obtained will be described in detail hereinafter. Furthermore, as heretofore stated, the rotation is such that the blades advance at the region of the rotor disc overlap, and will retreat at the outboard regions of the discs.

In the present instance there are three blades for each of the rotors 8 and 9. While, as hereinafter explained, the blade surfaces are streamlined to offer little resistance to air flow, yet each blade such as I5, has a helicoidal twist from root to tip, and all of the blades of a rotor cooperate when rotated to operate as an air screw. Furthermore, the arrangement is such that each of the rotor blades such as I5, may be angularly adjusted so as to vary the angle of attack of the blade surfaces, thereby providing the effect of a variable pitch for the air screw. By thus varying the effective pitch of the rotors, the lifting effect is correspondingly varied.

Although in the present instance a relatively low rate of rotor rotation is provided. of the order of 480 revolutions per minute, the rotor blades serve to lift the helicopter and to cause it to rise. The rate of rise may be effected by controlling the pitch of the blades. The specific mechanism whereby this can be effected will be described in detail hereinafter.

As heretofore stated, the rotors 8 and 9 rotate in opposite directions, and since the rotations are synchronous, the reaction torques opposed to the torques of the rotors, are balanced, and there is accordingly no tendency for the helicopter to turn about an axis parallel to the axes l0 and I l.

Each of the blades such as I5, is also provided with an aileron IT on the trailing edge near the tip of the blade. These ailerons are so arranged that they may be elevated or depressed with respect to the trailing edge of the corresponding blade l5. By appropriate control of the aileron elevation, it is possible to cause the helicopter to roll, pitch or yaw, as desired by the pilot.

As will be hereinafter explained, the ailerons such as I! are controlled so that they move, during one revolution of a rotor, to a maximum deviation, where they present a maximum angle of attack, and then they recede to a position Where the angle of attack is a minimum. This is a cyclic movement, in which one cycle is completed for each revolution; and the control is such that the aileron reaches the maximum angle of attack when the blade is in a definite angular position in its motion around the axis H) of the rotor 8.

If the ailerons are maintained in a neutral position without any cyclic deviation as the rotors rotat'e, the effect is indicated in the diagram of Fig. 40. Here the rotors 8 and 9 are diagrammatically illustrated, having their respective axes II) and 

